1. Field of the Invention
The present invention relates to a method for recycling a support material from an image bearing support which bears images thereon comprising a thermofusible ink, more particularly to a method for copy paper from an image bearing copy paper.
2. Discussion of Background
Because of recent rapid development of office automation, a large quantity of papers for printers and copying machines has been used and consumed. This has caused the problems of the environmental disruption of the earth due to deforestation.
Conventionally, in order to recycle papers of this kind, printed ink is removed from the paper, and the ink-removed paper is crushed and paper is made therefrom again. This has been an only method of recycling this kind of paper materials.
However, recently a method of recycling used copy papers by cleaning printed images off the surface of the copy paper has been developed, and examples of such a recycling method have been described, for instance, in the following references:
(1) Japanese Laid-Open Patent Application 4-64472:
A releasing agent such as a silicone sealing agent is applied to the surface of a new copy paper and dried to prepare a copy paper that can be recycled. Images are formed on the releasing agent applied surface of the copy paper.
The image-bearing-surface of the thus prepared copy paper is brought into contact with a thermofusible resin which is one of image formation components of the toner (hereinafter referred to as toner resin), and is caused to adhere to the thermofusible resin to remove toner images from the copy paper.
This method, however, has the following shortcomings:
(a) Since a releasing agent is applied to a copy paper, the image fixing performance thereof is poor as a matter of course. PA1 (b) The thermofusible resin is caused to adhere to the toner resin, which is one of image formation components, under the application of heat thereto, and toner images are mechanically peeled away from the surface of the copy paper. However, it is impossible to completely remove the toner resin since the toner resin penetrates into the fibers of the copy paper and firmly fixed thereto. Therefore, the recycling performance of this copy paper is extremely poor. PA1 (c) In view of the significance of recycling resources, duplex copies which bear images on both sides thereof are useful and will become very popular in the future. Under such circumstances, however, the method of producing copy papers for recycling by applying a releasing agent to one side of a copy paper is neither effective nor useful. PA1 (d) Even if the releasing agent is applied to both sides of the copy paper, as long as the releasing agent is a silicone sealing agent, it will penetrate into the copy paper and the copy paper will become semitransparent. If this takes place, that copy paper cannot be used as duplex copy paper. PA1 (e) When this erasable copy paper is mixed with plain copy paper, its distinction is not easy when used in practice, and its separation is not a practical operation for the efficiency of office work. PA1 (a) impregnating an image-bearing support, at least part of which is composed of a paper layer, and on which paper layer images made from a thermofusible ink containing a thermofusible resin component are formed, with at least one of water or an aqueous solution which is selected from the group consisting of an aqueous solution containing a surfactant, an aqueous solution containing a water-soluble polymer, and an aqueous solution containing a water-soluble polymer and a surfactant; (b) causing an image release member to adhere to the image bearing side of the support with the application of heat thereto, the image release member including a resin layer which is composed of the same thermofusible resin component as that contained in the thermofusible ink, or a resin layer having the same or substantially the same SP value (solubility parameter value) as that of the thermofusible resin component in said thermofusible ink; and (c) peeling the images away from the support, under the conditions that the thermofusible ink is fused, by removing the image release member from the support. PA1 SP value=8.0 to 12.0 (cal/cm.sup.3).sup.1/2
(2) Japanese Laid-Open Patent Applications 1-101576 and 1-101577.
A toner-image-bearing copy paper is immersed into an organic solvent in which the toner resin contained in the toner images of the toner-image-bearing copy paper is soluble, and is then subjected to an ultrasonic wave treatment, thereby removing toner images from the copy paper. This method, however, has the shortcoming that organic solvents used cause air pollution problems and are ignitable and toxic, accordingly not suitable for office or home use.
(3) Japanese Laid-Open Patent Application 1-297294
In this application, metal, paper into which liquids hardly penetrate, and ceramics are employed as the support of a toner-image-bearing member, plastics, and toner images formed on the support are heated through a thermofusible releasing member, whereby toner images are peeled off the support and the support is cleaned. In this method, however, a special erasable paper subjected to releasing treatment has to be used. Therefore, this method has the shortcoming that it cannot be applied to a large quantity of copy paper and printing paper now in general use.
Furthermore, the applicants of the present invention have proposed a method of using an ink-image-bearing support at least part of which is composed of paper, and causing an image releasing member to adhere to the support with the application of heat or pressure thereto, with water or an aqueous solution being contained therein, thereby peeling the toner images off the support and recycling the support. In this method, however, when the ink is not thermally fused, the ink is firmly deposited on the fiber of the support, so that when the ink images are peeled off the support, the surface of the support is considerably impaired.
The basic systems of electrostatic copying machines can be classified into three systems, that is, electrofax, xerography, and NP.